Furnace Odor Causes: Burning Dust, Must, Oil

There are a few ways you might be able to pick up signs of problems or other minor concerns in your HVAC system, and one of these is via smells. Certain notable odors may indicate issues in your system that need attention; on the flip side, some are relatively natural and aren't much cause for concern in many situations.

At My Buddy the Plumber, we're happy to help our clients with a variety of HVAC services, including basic furnace maintenance and repairs headed into the Utah winter. What smell is coming from your furnace, and is it normal or something you should be concerned about? This two-part blog series will go over everything you should know.

Burning Dust

Our first example of a furnace odor that likely isn't a major problem for you: Burning dust, which you'll often smell when running the furnace for the first time in the fall after a summer of it being off. This can happen when your system is running, too, but it'll be more noticeable during start up.

The source of the smell here comes from the dust and other particles that get stuck to your furnace's heat exchanger over time, from things like pet dander or pollen. Burning these off is just a part of the process, and it's completely normal.

Musty Smells

Musty odors are similar to burning odors -- but only to a point. That is, if you smell them immediately upon starting up your furnace for the first time in a while, there's typically nothing to worry about.

However, if this smell does not dissipate after a few minutes of use, or if it starts to smell more like a sewer than a damp basement, this could indicate a problem with your system's drainage or a mold issue. In these cases, you'll want to call our team to investigate.

Oil Smells

Here, again, is an example of the need for context. For instance, if your HVAC technician was recently at your home refilling your oil-based furnace, it's possible some lingering odors will be present for a few days, and this is no major concern.

However, if you smell oil for weeks at a time and there's no reasonable explanation, it's possible you have an oil leak or that the oil burner needs repair.

Electricity and Burning Smells

Finally, you might notice a burning smell when your furnace turns on and off, but not when it's running normally. This is another example of context playing a role: If you hear clicking and see flickering lights and then get a whiff of burnt electricity, it could be because your capacitor is aging and needs to be replaced.

On the other hand, if you don't hear anything unusual but still smell electricity, this might point to issues with the wires in your furnace or another component. Call our team for help!

For more on the various odors that may come from your furnace and whether they're cause for concern, or to learn about any of our furnace repair or other HVAC services, speak to the staff at My Buddy the Plumber today.